Process of and apparatus for the destructive distillation of wood.



A. CAMERON.

PROCESS OF AND APPARATUS FOR THE DESTRUCTIVE DISTIL LATION 0F WOOD.

APPLICATION FILED SEPT- 26, 1913.

1,137,255. Patented Apr. 27, 1915.

3 SHEETS-SHEET I- A. CAMERON.

PROCESS OF AND APPARATUS FOR THE DESTRUCTIVE DISTILLATION 0F WOOD.

APPLICATION FILED SEPT. 26, 1913.

1 1 37,255. Patented Apr. 27, 1915.

3 SHEETSSHEET 2- A. CAMERON. PROCESS OF AND APPARATUS FOR THEDESTRUCTIVE DISTILLATION 0F WOOD.

. APPLICATION FILED SEPT. 26, 1913. 1 ,137,255, Patented Apr. 27, 1915.

v a SHEETS-SHEET a.

ALEXANDER CAMERON, OF EAST JORDAN, MICHIGAN.

RBOCESS OF AND APPARATUS FOR THE DESTRUCTIVE DISTILLATION OF WOOD.

Specification of Letters Patent.

Patented Apr. 2'7, 1915.

Application filed September 26, 1913. Serial No. 791,891.

To all whom it may concern Be it known that I, ALEXANDER CAMERON, acitizen of the Dominion of Canada, residing at East Jordan, in thecounty of Charlevoix and State of Michigan, have invented a certain newand Improved Process of and Apparatus for the Destructive Distillat onof Wood, of which the following is a specification.

This invention relates to an improved process of and apparatus for thedestructive distillation of wood, and it has for its salient objects toprovide for the recovery of a larger percentage of wood alcohol, acetateof lime and other by-products; to provide for the carrying out of theprocess to-completion at a markedly lower temperature and with equalrapidity, or even more rapidly than in accordance with the best practiceheretofore known; to effect a corresponding economy of fuel; toeflect avery large saving in the way of malntenance by reason of the much lowertemperature at which the process is conducted; to greatly shorten thelen h of time required for cooling the resulting charcoal to a conditionin which it may be safel to insure a more uni orm and certain reductionof all parts of the wood to charcoal; and in eneral to provide animproved process an apparatus of the character referred to.

The invention will being had to the accompanying drawings illustratingsuitable apparatus for carrying the process into effect, and in whichdrawings, Figure 1 is a view partly in elevation and partly in section,showingamain. retort housed in, two cooling retorts and a-singleso-called buggy or car arranged in one of the retorts; Fig. 2 is an endelevation of one of the buggies embodying my apparatus imrovements; Fig.3is a plan view of a buggy;

ig. 4: is aside elevation of an end portion of one of the buggies,showing a charge which has been reduced to charcoal; and Fi 5 is asimilar view of an end portion of a buggy partly loaded and ready to beshifted mto the retort.

In the destructive distillation of wood as now practised in the mostmodern way heretofore' known, the wood, commonly in the shape ofcord-wood, is piled into metal buggies or cars of openwork construction,and rolled into a long tubular steel or iron rehandled and shipped;

be readily understood. from the following description, reference'.

tort, which is sealed except for the outlets for vapors and gaseousproducts of distillation. This retort is arranged above a suitablefurnace and is bricked in by surrounding walls. After the destructivedistillation has been completed by the furnace heat applied to theretort, the buggy containing the charcoal is removed from the retort andwheeled into a cooling chamber or secondary sealed retort, and allowedto partly cool. Inasmuch as it is found in practice that it requiresabout twice as long to cool the charge down to a temperature where itcan be safely exposed to the outer atmosphere as it does to distill it,it is customary to employ a pair of cooling retorts, a partly cooledcharge being transferred from the first cooling retort to the secondcooling retort, the

two retorts thus serving to accommodate one distilling retort operatingcontinuously, or ractically so.

ccordlng to the old 'practice,the wood to i be reduced was piled intothe crate or openwork box of the buggy until the latter was sufficientlynear full, and without any attempt to separate the wood into layers, butsimply allowing the entire pile to rest upon the bottom of the box andconfined against lateral movement by the sides of the crate. As theprocess of distillation proceeded, the wood shrunk and settled, becomingmore and more compact as the process proceeded, un-

til at the conclusion the charcoal was in the .form-of a comparativelydense mass resting upon the bottom of the car.

.The apparatus shown in the drawings herein is. of a common typeheretofore known, except only that the buggies are of modifiedconstruction, as will hereinafter appear.

Referring to the drawings, 1 designates as a whole the main ordistilling retort, which is arranged within a surroundin brick setting2, leaving the 'end doors 3 an 4 of theretort exposed, and, for betterprotection against the weather, arranged within a shed or housingdesignated as a whole 5. Beneath the retort is arranged a furnacecomprising a pair of grates 6, 6 arranged at the respective ends of thefurnace, an intervening combustion chamber 7, and an overlying arch 8,which is spaced some distance below the lower side of the retort, asshown clearly in Fig. 1. Over each grate is arranged a fuel inlet-pipeor hopper 9, through .which the grates may .be supplied,

The doors 3 and 4 constitute the end walls of the retort, and are hingedas indicated at 3 and I, so that they may be swung open to admit thebuggies.

Track rails 10 are arranged to extend longitudinally through the retort2, as well as through the cooling retorts or chambers designated as awhole 11 and 12, respectively. The retorts 11 and 12 are in generalsimilar to the retort 1 except that the outside jacketing of brick isomitted.

The distilling retort 1 is provided with one or more outlet pipes 13,which lead to suitable condensing apparatus, not shown.

Now, describing the construction of the buggies, each vehicle isprovided with a suitable skeleton base-frame designated as a whole 15,and carried on a pair of wheeled axles 16, the wheels 17 of which arearranged to' traverse the tracks 10 hereinbefore described. The floor ofthe vehicle is of slatted construction, as shown plainly in Fig. 3; theslats being suitably spaced so as to prevent the charcoal from fallingthrough, while at the same time affording free acccssfor the circulationof air through the door. The sides and ends, designated 18 and 19, arealso of slatted construction, being preferably provided with uprightslats 20 secured to suitable horizontal strips 21, which are in turnsecured-to the corner posts 22 of the box. The slats of the sides andends are desirably spaced apart more widely than those of the floor, soas to afford i freer circulation of the air and avoid superfluousweight.

T he distinct feature of improvement of the present apparatus resides inproviding means whereby the charge of wood is supported in layers so tospeak, and prevented from settling down into a single compact mass inthe bottom of the buggy. To this end I provide sets of cross bars,severally designated 23, which cross bars are spaced at suitableintervals apart to support the sticks of wood, and eventually come torest on the horizontal bars 21 of the end walls of the bugg -box.According to the old practice, the wood was piled into the buggies,resting on the bottom, and rising as hi h as was desired. In the use ofmy present apparatus and in carrying out the improved process hereindescribed, a first layer of wood is piled into the bottom of theboxuntil it rises to a point somewhat above the lower set of endcross-bars 21, whereupon the first set of supporting rods or tubes 23 isinserted so that the several bars or tubes extend through the spacesbetween the upright slats and rest on top of the wood. The filling in ofthe wood is then resumed until the pile has risen a short distance abovethe second set of end cross-bars 21, whereupon a second set ofsupporting tubes or rods 23 is inserted as before, and

then the remainder of the charge of wood is piled in on top of these. Bypiling in the wood and inserting the supporting bars in the mannerdescribed, I avoid carryin the' entire weight of the upper layers of thewood directly upon the unsupported bars 23; it being obvious that thepieces of wood underneath them and upon which they rest aid insupporting the wood piled in above. \Vhen the distillation takes place,the first stages of the process drive off the free water, thus verygreatly reducing the weight of the wood, and at the same time causing itto shrink considerably. Before the wood has shrunk enough to allow theseparating rods 23 to descend into bearing with the cross strips 21, theweight of the wood has been greatly reduced, so that the rods are amplystrong to support whatever weight comes upon them.

In carrying out my improved process by the use of the apparatusdescribed, I proceed substantially as follows: The retort being hot, anumber of buggies loaded with Wood in the manner described are run in tothe retort, end to end, and the doors of the retort closed, whereuponthe firing is continued to bring about the distillation. The temperatureis raised steadily until the vapors of distillation begin to flow freelyfrom the wood, and is then maintained under such control as to insure acontinuance of the free flow of vapors. In accordance with the oldpractice, the temperature was raised steadily from approximately 500 or550 Fahrenheit (which may be assumed as the temperature at which theretorts would be when the buggies were inserted) until in the course ofabout four and one-half or five hours the temperature would range wellabove 800, and often as high as 900. Having reached this temperature ofsay 850, the firing was so conducted as to maintain the temperatureabout the same until the distillation was nearly completed; thetemperature being allowed to fall perceptibly at about the end of theseventeenth or eighteenth hour. Thereafter the heat of the kiln was inpractice found sufiicient to continue the process to a conclusion; thetemperature gradually descending so as to approximate 600 at the end oftwenty hours.

In accordance with my improved process, the temperature is raisedgradually from the time the retort is closed until it reachesapproximately 700 Fahrenheit, which will be at the end of about fourhours time. At

this time the vapors of distillation begin to run very freely, indeed sogreat is the evaporation that the temperature within the kiln decreasesto a marked extent. In the demonstrative run in which the temperathreehours later the temperature had descended to well below 600, although.an ample flow of vapors had been maintained. From this time, however,it was necessary to increase the fire so as to raise the tem erature, inorder to maintain the desired ow, and the temperature had, at the end ofthe twelfth hour, again risen to about 700. From this point to near theend of the process the temperature remained nearly uniform and slightlyabove 700; decreasing, of course, when the fires were withdrawn in thelast stage of the process.

By making comparative runs under precisely similar conditions as regardsapparatus and wood treated, I found that in accordance with my improvedprocess the average temperature was fully 170 lower than under the oldprocess, and that during a long stretch of time in the intermediate partof the process the temperature was approximately 250 below thatnecessary in the old practice. I also determined that even with thesestrikingly lower temperatures the charge was completed, 11. e.,completely reduced to charcoal, within a period of about twenty hours;this being approximately the same length of time required under the oldprocess. Besides the markedly lower temperature employed in my newprocess, I found that I recovered a much larger yield of alcohol and ofacetate of lime. That is to say; in the demonstrative runs which I havemade I secured fully 20% increase of alcohol, and over 32% of increasein the yield of acetate of lime. These results are easily accounted forby the fact that the distillation is effected at markedly lowertemperatures. That is to say, the higher the temperature employed, thegreater is the percentage of molecular destruction and consequentconversion of the products into permanent gases which cannot berecovered as distillates.

The fact that the process can be conducted at the relatively lowtemperatures described must, I think, he explained by the arrangement ofthe charge within the buggies in layers, 71. 6., in such manner that theheat readily permeates all parts of the mass uniformly almost from thevery beginning of the process. This uniform distribution of the heat isof great importance not only in protecting certain portions againstoverheating and consequent loss of yield, but also in bringing about auniform reduction of the wood to charcoal in a minimum length of time. Ihave found that with my improved method there is no uncarbonized woodleft in the buggy at the end of the process, whereas under the oldpractice it was very common to find chunks of partially carbonized wood,notwithstanding the process had been conducted at the much higher rangeof temperatures. This uniform reduction of the wood to charcoal isanitem of fieat importance, inasmuch as the charcoal s a strong tendencyto ignite when it is exposed to the outer air, which tendency is muchstronger if the charcoal is not perfectly carbonized. Moreover, the factthat the charcoal at the conclusion of the process, as conducted inaccordance with my improvements, is in the condition of separatedlayers, insures a much more rapid and uniform cooling down of thecharcoal when it is transferred to the cooling retorts, so that on thewhole the process is materially shortened, as well as im rovedgenerally.

Itwill be understoo that after the distillation has been completed inthe distillation retort, the retort is opened and the buggiestransferred to the next cooling retort, the same as in the prior artpractice, and after being there partly cooled, againtransferred to thefinal cooling retort, where the cooling is completed sufiiciently topermit the mass to be exposed to the atmosphere without danger.

It will be understood from the foregoing description that the salientfeature of my improvement resides in the discovery that by separatingthe charge into layers or comparatively small bodies to which the heathas free access, the distillation may be effected at very much lowertemperatures without prolonging the time, and with improved results inthe way of increased yields, more rapid cooling of the charcoal, etc. Itwill be understood therefore that the rocess is not limited to the useof thespecific apparatus herein shown and described, although thatapparatus is admirably adapted for carrying out the process.

I claim as my invention:

1. The improvement in the art of destructively distilling cord-wood,which consists in arranging the wood in orderly-piled adj aoentsuperimposed layers, the under side of each upper layer and the upperface of the lower layer being exposed to permit air to circulate incontact with said adjacent side and face, inclosing the charge in asealed retort, progressively destructively distilling same by theapplication of controlled supplies of externally applied heat, andprogressively effecting a separation of said layers by permitting saidlayers to shrink in thickness independently during the distillationprocess in order to form distinct bodies of charcoal with circulationspaces between them.

2. The improvement in the art of destructively distilling cord-wood,which consists in cording the wood in overlying proximate layers havingtheir adjacent surfaces exposed and separated by inchoate circulationspaces, and carried by a common support, inclosing the charge on saidsupport in a sealed retort, progressively distilling the same by theapplication of controlled supplies of externally applied heat, andeffecting progressive separation of said layers and a evelopment of saidcirculation spaces to an effective value by substantially confining themovement due to shrinkage to the respect'ive layers.

3. In charcoal burning apparatus, the combination of a sealed retort, aplurality of incombustible cross-members adapted to divide the charge ofwood into horizontal layers vertically spaced apart from each other,said members at the commencement of the process being in contact withboth layers between which they are interposed, and a plurality ofopposed supports adapted to engage said cross-members and support saidupper layer upon shrinkage of said lower layer during the distillationprocess.

4. In charcoal burning apparatus, the combination of a sealed retort, aplurality of incombustible cross-members interposed between twohorizontal layers of WOOd to be distilled and supported at thecommencement of the process by the bottom layer, and a pair of opposedsupports adapted to engage said cross-members and to support saidmembers and said upper layers upon shrinkage of the lower layer duringthe distillation process.

5. In apparatus for destructively distilling wood, the combination of asealed retort, -a wheeled skeleton car provided with laterally extendingsupports at two of its opposed sides, and a plurality of detachedincombustible cross-members adapted to be interposed between horizontallayers of wood supported on said car and at the commencement of theprocess adapted to be supported by the lower layer of wood out ofcontact with said opposed supports, but long enough at each of theirends to project from between said layers and engage said supports uponshrinkage of said lower layer during the distillation process.

6. The improvement in the art of destructively distilling cord-wood,which consists in disposing the wood in a plurality of contiguoussuperposed distinctly sectionalized bodies having their adjacentsurfaces exposed relatively to each other carried by a suitable commonportable support, inclosing the charge in a sealed retort, applying heatthereto and utilizing the shrinkage of wood during the distillationprocess to effect a substantial separation of said bodies of wood andform comparatively large circulation passages between said bodies, andremoving the charge into a cooling medium whereby the cooling of saidcharge is hastened by the previous formation of said circulation spaces.

ALEXANDER CAMERON.

Witnesses:

NELSON CRANDALL, JAY J. TROMBLY.

